Exhaust valve mechanism



NOV. 1, 1932. EL ER Lg fiii EXHAUS T VALVE MECHAN I SM Filed July 9, 1928 3 Sheets-Sheet l INVEN TOR.

ATTORNEYS.

NOV. 1, 1932. ER 1,886,212

EXHAUST VALVE MECHANISM Filed Jul 9, 1928 s Sheets-Sheet 2 gab I: agma M- h l as is :4 Q Q NV N TOR.

A TTORNEYS.

. Nov. 1, 1932. H. G. MUELLER EXHAUST VALVE MECHANISM Filed l 9, 1928 3 Sheets-Sheet s IN VEN TOR.

ATTORNEYS.

mmwmm Patented Nov. 1, 1932 UNITE eras I HERMAN G. MUELLER, OF ERIE, PENNSYLVANIA, ASSIG-NOR .TO SKIN'NER ENGINE COMPANY, OF. ERIE, PENNSYLVANIA,

ECE

A COR?ORATION OF PENNSYLVANIA.

EXHAUST VALVE IMECHANISIVI Application filed July 9, 1928.

This invention is designed to improve and simplify exhaust valve mechanisms.

' a yielding seat which is cushioned by the steam pressure. Features and details of the invention will appear more fully from the specification and claims.

A preferred embodimentof the invention is illustrated in the accompanying drawings as follows Fig. 1 shows an elevation, partlyin sec tion of an engine having the exhaust valves The valve is prov ded with a stem 18, which of my invention.

Fig. 2 a detail view of the actuating shaft mechanism.

. Fig. 3 an enlarged sectional view of the,

cylinder and exhaust mechanism. a

1 marks an englne frame, 2 an englne cylinder, 3 inlet ports to the enginewhich are controlled by inlet valves (not shown), 4: central exhaust ports, 5 an exhaust passage to .7 which the central exhaust ports lead, 6 an elongated piston of uniflow type operating over the central exhaust ports, to auxiliary exhaust ports, 7 an exhaust valve chest, 8 a discharge port from the exhaust valve chest and 9 a passage leading from the port 8 to the general exhaust passage 5.

A yielding valve seat 10 is arranged in the exhaust chest 7. The yielding seat is ringshaped and provided with a shoulder 11 resting on a shoulder 7a in the chest 7, these shoulders limiting the movement of the yielding seat in a seating direction. A seat case 12 is arranged around the yielding seat 10 and is seated on the shoulder 7 a in the chest 7 and held upon its seat by screws 12a extending through a valve chest cover 126. The case has an annular pocket 120 in which is arranged a split sealing ring 13. The sealing ring is provided with a groove in which In some of its aspects it is of general applica struction. A spring 13bsurrounds the ring Serial No. 291,358.

13 and tends to hold it in engagement with the yielding seat.

Passages 1 1 connect the pocket 120 with the exhaust port 4a. Theupper face-of the shoulder 11 has a greater area than the lower face of said shoulder and being subjected to the steam pressure of the exhaust port tends to hold the yielding seat in its downward position. Springs 10a extend into sockets 10b in the shoulder 11. These-springs .are seated against a plate 130 resting under the ring 13. v j

A valve 15 has a seating surface 16 which operates upon a seating surface 17 on the edge of the movable seat 10. The valveand seat are of the same diameter so that when closed there is no appreciable separating pressure exerted on the movable seat and valve.

stem is provided at its end with a cam roller 19. The cam roller operates on a cam 20, the cam being fixed on a shaft 21. The shaft 21 is driven through gears 21a and 216 from a vertical shaft 22 and the vertical shaft is in turn driven from the crank shaft through suitable gearing in the usual manner, as indicated in dotted lines in Fig. 1. The valve is provided withthe usual seal mg ring 15a and a passage 15?) connects a groove 150 containing the sealing ring with the exhaust port so that the sealing-ring is subjected to exhaust port pressure.

A spring 23 operates onthe valve 15 and opens the same when the valve is released by the cam 20. The spring is seated on a plate 23a and is adjusted by means of a screw 236, the screw extending through the cover plate 12?). i

The lower end of the Valve chest is closed and thus a chamber is formed under the valve. This chamber communicates with the atmosphere through a passage 24 which passage is provided with a non-return check valve 25 ordinary timing of valves of this type. The valve remains seated during the expansion stroke of the cylinder and opens approximately at the time of opening of the central ports by the piston. It remains open during the return stroke of the piston until the piston has passed the port la. The valve is closed at any time after the closing of the .port by the piston and prior to. the return of the, piston to this port. Ordinarily the valve 15' is closed immediately'after the piston covers the auxiliary port. It will be seen,- therefore, that it is only necessary to provide a spring 23 of suflicient strength to open the valve with the aid of the slight differential between the partial vacuum; below the valve and the preponderant exhaust port pressure above. the valve when the engine is operating without condensing the. exhaust. On the other hand, in closing the valve it is only necessary for the cam to overcome the spring 23 and the preponderant exhaust port pressure on the upper surface of the valve and the very slightresistance. to movement on the valve seat. The closing pressure on the valve seat, as before stated, is supplied as the steampressure builds upin the port M.

In operation,the valve is positively closed by the cam operating on the stem, the valve raising the seat slightly to assure a closure at each operation. Thisclosure of the valve in thepresent instance requires a seating pressure corresponding only to the steam pressure at the moment of closing, the steam backing of'the movable seat controllingthis seating pressure, the springs 10a being so slight as to add very little to the steam pressure.

' Inmy prior applicationthe movable seat was subjected to a. spring pressure for holding it in yielding seatingposition. It was necessary with that, construction to. supply a spring of suflicient strength to force the movable seat forward under the maximum pressure to which it-was subjected: This placed. a very substantial loadon the cam and'roller which involved wear andtook some power. With the present invention the movable seat is loaded with a steam pressurecorresponding to the pressure in the port and therefore, the load on the cam is in each instance as slight as is practical.

auxiliary exhaust the ring pressure at the time of the movement of-the movable seatis very slight.

As, in my prior application the exhaust of air from the valve chest under the valve 15 adds to the-effectiveness of the -spring ;23 in opening thevalve in that -it creates-a sub Further the steam pressure back of the ring 13 is slight atthe time of movement ofv the movable valve butatmospheric condition under the valve against which the ordinary exhaust operates.

Also when the engine exhausts to a condenser the sub-atmospheric condition created by the condenser communicated from the exhaust passage by the passage 9 and port 8 reduces the pressure above the valve 15 so that the closing pressure on the valve is greater than the spring pressure and, therefore, the auxiliary valve under these conditions does not open'sothat the engine operates perfectly condensing and non-condensing with no attention whatever on the part of the operator. It will; be understood that the condenser pressure is much below the small pressuredifference below atmosphere which it is possible to create under the valve 15 by reason of pumping action.- through the passage 2 L past the check 25.

What I claim as new is 2- 1. In an exhaust valvemechanism, the com- 4 bination of a cylinder having an exhaust port and anexhaust valve chest communicating with theport; a seat case inthe chest forming a closure withthe'walls of the chest; a yielding-seat carried by the case witha. steam space between the seat and the case, the seat, presenting a preponderant pressure face yieldinglyholding the seat in: position; a. steam connectionleadingtosaidv space from a. pressure source having a pressure approximating the pressure of'th-esteam.onthe valveg; and a valve operatingonthe seat.

2. In an exhaust valve. mechanism, the combination ofia cylinder havingan exhaust, port andan exhaust valve chest communicating with the port; a seat case in the chest forming a-closure with thewalls of the chest; ayiel'ding seat carried bythe case with a steam space between the seat and the case, theseat presenting a preponderantv pressure face yieldingly holding the seat in position; a

steam connection leading to said space, said pressure corresponding to the pressure in said space. 1

'3, In an exhaustvalve mechanism,- the combination of' a cylinder havinga central exhaust port; an auxiliary exhaust port; an exhaust valve chest communicating with the auxiliary exhaust port; a seat case inthe chest forming closure with the walls ofthe chest; ayielding seat carried by said case with a .steam'space between the seat and the case, theseatpresenting preponder-..

ant pressure faceyieldingly holding the seat in position; a steam. connection leadingto said space; from a pressurersource. having a pressure approximating the pressure of the steam at the. valve; a valve operatingontheseat; a cam closing the valve; and a spring opening the valve.

4:. In an exhaust valve mechanism, the combination of a cylinder having a central exhaust port; an auxiliary exhaust port; an exhaust valve chest communicating with the auxiliary exhaust port; a seat case in the chest forming a closure with the walls of the chest; a yielding seat carried by said case with a steam space between the seat and the case, the seat presenting a preponderant pressure face yieldingly holding the seat in position; a steam connection leading to said space, said connection leading from a steam source having a pressure approximating the pressure of the steam at the valve; .a valve operating on the seat; a sealing ring between the seat andcase, said ring being subjected to steam pressure corresponding to the pressure in said space; a cam closing the valve; and a spring opening the valve.

In an exhaust valve mechanism, the combination of a cylinder having an exhaust port; an exhaust valve chest communicating with the port; a valve controlling said port; a

yielding seat in the chest on which the valve operates, said seat being steam-loaded from a pressure source approximating the pressure of the steam at the valve; and means closing the valve while the valve is subjected to a reduced pressure.

6. In an exhaust valve mechanism, the combination of a cylinder having an exhaust port; an exhaust valve chest communicating with the port; a valve controlling said port; ayielding seat in the chest on which the valve operates, said seat being steam-loaded from a pressure source approximating the pressure of the steam at the valve; and means opening and closing the valve while the valve is subjected to a reduced pressure.

7 In an exhaust valve mechanism, the combination of a cylinder having an exhaust port; an exhaust valve chest communicating with the port; an exhaust valve controlling said port; a yielding seat in the chest on which said valve operates, said seat being steam-loaded from a pressure source approximating the pressure of the steam at the valve; a cam closing the valve while the valve is subjected to a reduced pressure; and a spring opening the valve.

8. In an exhaust valve mechanism, the combination of a cylinder having an exhaust port; an exhaust valve chest communicating with the port; an exhaust valve controlling said port; a yielding seat in the chest on which said valve operates, said seat being steam-loaded from a pressure source approximating the pressure of the steam at the valve; a cam closing the valve while the valve is subjected to a reduced pressure; and a spring opening the valve while the valve is subjected to a reduced pressure.

9. In an exhaust valve mechanism, the

yieldingly holding the seat in position; a

steam connection leading to the space from a source of pressure coresponding to the pressure to which the valve is subjected; and means closing the valve while the valve is subjected to a reduced pressure.

In testimony whereof I have hereunto set my hand.

HERMAN G. MUELLER. 

